AO* revisited

Abstract:

This paper revisits the AO* algorithm introduced by Martelli and Montanari [1] and made popular by Nilsson [2] The paper's main contributions are: (1) proving that the value of a node monotonically increases as the AO* search progresses , (2) proving that selective updates of the value function in the AO* algorithm are correct and
providing guidance to researchers interested in the AO* implementation. (1) and (2) are proven under the assumption that the heuristic used by AO* is consistent. The paper also reviews the use of AO* for solving Markov Decision Processes (MDPs) and Partially Observable Markov Decision Processes (POMDPs).